1. Field of the Disclosure
The disclosure relates to a gate line driving module for a liquid crystal display (LCD), and more particularly, the disclosure relates to a gate line driving module and an LCD which use clock signals to serve as a high level gate power source.
2. Description of Related Art
FIG. 1 is a schematic view of a typical thin film transistor liquid crystal display (TFT-LCD) 100. As shown in FIG. 1, the TFT-LCD 100 includes a liquid crystal (LC) panel 110, a gate line driver 120, and a plurality of data line drivers 130, 140, and 150. The gate line driver 120 and the data line drivers 130, 140, and 150 drive corresponding thin film transistors (TFTs) on the LC panel 110. In order to reduce the cost of manufacturing TFT-LCDs, it is currently considered that the gate line driver and the LC panel are fabricated on the glass substrate in an identical process. By such a manner, the cost of additionally disposing the gate line driver on the LCD and the area of the integrated circuit are both saved.
However, fabricating the gate line driver on the glass substrate in the amorphous silicon process has the limitation of which the gate line driver is simply implemented by N-type TFTs. As a result, a high level gate power source of the gate line driver must be supplied, such that the switch states of the internal switches are determined. However, the electron mobility of amorphous silicon is relatively low, width to length (W/L) ratios of the N-type TFTs adopted in the gate line driver must be relatively high to offset the low electron mobility of amorphous silicon. As a result, internal parasitic capacitance of the gate line driver is increased, such that the phenomenon of coupling between internal signals of the gate line driver is easily generated due to the increase of the parasitic capacitance. Accordingly, the output signals of the gate line driver creates a ripple effect, such that the display quality of the LC panel is affected. Furthermore, in the gate line driver, the N-type TFTs which are affected by bias over a long period of time have the phenomenon of device characteristic drift, so as to affect the operation of the gate line driver.